UNS C38000 (CW624N) Leaded Brass
C38000 brass is a brass formulated for primary forming into wrought products. Cited properties are appropriate for the M20 (as hot rolled) condition. CW624N is the EN numeric designation for this material. C38000 is the UNS number. Additionally, the EN chemical designation is CuZn43Pb2Al.
It has a moderately low base cost among wrought brasses. In addition, it has the lowest melting temperature and a moderately low tensile strength.
The graph bars on the material properties cards below compare C38000 brass to: wrought brasses (top), all copper alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
100 GPa 15 x 106 psi
Elongation at Break
17 %
Poisson's Ratio
0.31
Shear Modulus
39 GPa 5.7 x 106 psi
Shear Strength
230 MPa 34 x 103 psi
Tensile Strength: Ultimate (UTS)
380 MPa 55 x 103 psi
Tensile Strength: Yield (Proof)
120 MPa 18 x 103 psi
Thermal Properties
Latent Heat of Fusion
170 J/g
Maximum Temperature: Mechanical
110 °C 230 °F
Melting Completion (Liquidus)
800 °C 1470 °F
Melting Onset (Solidus)
760 °C 1400 °F
Specific Heat Capacity
380 J/kg-K 0.091 BTU/lb-°F
Thermal Conductivity
110 W/m-K 66 BTU/h-ft-°F
Thermal Expansion
21 µm/m-K
Otherwise Unclassified Properties
Base Metal Price
22 % relative
Density
8.0 g/cm3 500 lb/ft3
Embodied Carbon
2.7 kg CO2/kg material
Embodied Energy
46 MJ/kg 20 x 103 BTU/lb
Embodied Water
330 L/kg 39 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
50 MJ/m3
Resilience: Unit (Modulus of Resilience)
74 kJ/m3
Stiffness to Weight: Axial
7.1 points
Stiffness to Weight: Bending
19 points
Strength to Weight: Axial
13 points
Strength to Weight: Bending
14 points
Thermal Diffusivity
37 mm2/s
Thermal Shock Resistance
13 points
Alloy Composition
Among wrought copper alloys, the composition of C38000 brass is notable for including aluminum (Al) and containing a comparatively high amount of lead (Pb). Aluminum is used to add strength and oxidation resistance. Lead is used to improve machinability and bearing properties, at the cost of toxicity.
| Cu | 55 to 60 | |
| Zn | 35.9 to 43.5 | |
| Pb | 1.5 to 2.5 | |
| Al | 0 to 0.5 | |
| Fe | 0 to 0.35 | |
| Sn | 0 to 0.3 | |
| res. | 0 to 0.5 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B455: Standard Specification for Copper-Zinc-Lead Alloy (Leaded-Brass) Extruded Shapes
ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001